Nowadays, press-keys are frequently in many electronic devices, such as computer keyboards, cellular phones, telephones, and so on. For enhancing the typing comfort of the press-key, manufacturers must have a proper resilience mode relating to the typing of press-key that are concluded from many years of experiment so as to obtain measurements relating to the performance of the press-keys during manufacturing. Therefore, there are already many devices for measuring the resilience of press-keys that are currently available.
One of which is a resilience measurement instrument disclosed in TW Pat. Pub. No. 529714. Operationally, the measurement instrument being mounted on a buffer base is positioned on a motor-driven lifting board while enabling a probing rod of the measurement instrument to abut against a press-key, by that the resilience relating to the pressing keystroke as well as the raising keystroke of the press-key can be measured. Moreover, as the rotation speed of the motor used for driving the lifting board is designed to be controlled by several micro switches disposed on the buffer base, the resilience measurement not only can be performed rapidly and accurately, but also the operation of the resilience measurement can be performed reliably without being affected by human error.
Nevertheless, the aforesaid resilience measurement instrument may be sufficient for those press-keys only capable of moving linearly downward by pressing or raising linearly upward by resilience, but they might not be suitable for measuring wind instruments such as saxophone, since the press-keys of those musical instrument are configured to pivot around a shaft relating to their master bodies in a reciprocating manner so as to control the opening/closing of their sound holes. Thus, for those press-keys fitted on wind instruments, a measuring device capable of obtaining the relationship between the resilience and displacement of the press-keys is required as the measurement of only their resilience performances is not sufficient. Thus, it is in need of an improvement over the aforesaid resilience measurement instrument.
There is a displacement measuring technique disclosed in U.S. Pat. No. 6,839,957, entitled “Displacement Unit”, which is a displacement unit using a hydraulic means for measuring displacement. It is noted that the displacement unit of the aforesaid U.S. patent uses a drive actuated by pressure fluid for driving a sliding component to move and then measure its displacement in consequence. However, since the size of the aforesaid displacement unit is too big and is not able to measure resilience, it is not suitable for measuring press-keys of wind instruments.
Moreover, since the press-key for those tube-like wind instruments are distributed on their circumferences at different radial angles, the devices such as the aforesaid displacement unit that are only capable of performing a displacement measurement along a direction perpendicular to their operation platforms are not suitable for measuring those musical instruments whose press-keys are disposed with different radial angles on their circumferences.
Therefore, it is common to use a retractable micro-force meter in cooperation with a scale measuring apparatus, or a large servo motor, to measure the press-keys of wind instruments for obtaining information relating to their resilience and displacement. However, such measurement is disadvantageous in its bulky size and high cost.
Although there is an alternative laser displacement measuring technique capable for the measurement, it is also too costly to operation as the laser distance meter can be very expensive.